Big heavy bull calves were to blame for the high rate of caesarean sections in the Derrypatrick herd this year, new analysis from Teagasc Grange has revealed.
A review of calf birth weights on the farm showed that those born by caesarean section weighed up to 14kg heavier than the calves born naturally.
Dr Eddie O'Riordan and Bernard Smyth from Teagasc Grange said the incidence of caesarean sections was much higher than expected, with nine sections carried out on the original herd cows, two on the original heifers and four sections on pregnant cows bought in as replacements.
"Caesareans were associated with male calves, with high birth weight relative to average birth weight and relative to cow liveweight after calving," the researchers said.
The caesareans occurred throughout the calving season and were not obviously related to cow body condition score or cow feeding, as all cows were treated the same, or to any sire breed, the resarchers insisted.
An analysis of the deaths on the farm showed that five calves were stillborn, three died at calving, two died due to deformity and one calf was crushed by its dam. There were no calf deaths due to caesarean section.
The review of calving performance was carried out ahead of tomorrow's open day at the farm, where Teagasc staff are expected to face a grilling from farmers over the herd's performance.
Meanwhile, the indications are that the offspring from the Limousin-cross Friesian cows in the herd produce heavier calves at weaning due to higher levels of milk production.
Last year, milk yield was highest for Limousin-cross Friesian cows and differences in calf pre-weaning growth between the cow breed types largely reflected differences in milk yield.
Over a 230-day pre-weaning, calves from the Limousin-cross Friesian cows finished 48kg heavier than the Charolais-cross Limousin ones and about 26kg heavier than those from Limousin-cross Simmental and Charolais-cross Limousin cows.